1. Field of the Invention
The present invention is directed to a radiation-sensitive transducer of the type having a sensor disposed on one side of a substrate having printed conductor runs therefor, with the sensor being glued over a large surface area on this side of the substrate. As used herein, a radiation-sensitive transducer means a transducer which converts incoming electromagnetic radiation into an electrical signal (current).
2. Description of the Prior Art
Monocrystalline light-sensitive sensors (e.g. CCDs or photodiode arrays) must often be of large-area construction and fastened to a mounting plate. From the mounting plate, the electrical connection of the sensor and the mechanical fastening in the system can ensue. For this purpose, the sensor is usually connected fixedly to the mounting plate (e.g. glued). When temperature variations occur, the surface of the sensor forms a bend (in the case of a one-dimensional (strip) sensor) or a spherical surface (in the case of a two-dimensional sensor). This can make the coupling to an optical (e.g. fiber optical) system or to an image converter (e.g. scintillator) more difficult, and can lead to loss of light or sensitivity, or MTF loss, in the regions wherein an enlarged coupling gap exists.
For these reasons, in German OS 195 46 423, corresponding to U.S. application Ser. No. 08/740,489, filed Oct. 30, 1996, now abandoned, ("Radiation Sensitive Transducer Wherein Deformation Due to Temperature Fluctuations Is Avoided," Sklebitz et al., assigned to the same assignee as the present application), a radiation-sensitive transducer is disclosed in which, in order to avoid the unwanted formation of a spherical CCD surface, during packaging a radiation-sensitive sensor is glued over a large surface to the front side of a mounting plate (i.e., a substrate), and a large-surface "dummy" component with approximately the same dimensions and the same thermal expansion behavior as the sensor is glued to the back side. By means of these measures, a problem-free coupling to a flat fiber optic plate is achieved.
For the manufacturing of a CCD ceramic Si dummy sandwich of this sort, relatively large-surface gluings are required, in which it cannot be avoided that gas pockets arise during the gluing that have an adverse effect on the quality of the gluing.
In order to achieve the symmetry required for both sides of the ceramic substrate (which may consist of other materials), the conductor runs are printed on the ceramics in the standard manner for hybrid technology and are constructed with approximately the same surface and directionality as the runs on the opposite side. These printed conductor runs are slightly raised in relation to the level of the substrate surface (e.g. by about 10 microns). Since in general two planes (levels) of printed conductors are employed, gas volumes become trapped in this recess at the ceramic substrate surface by the adhesive film which is applied thereover, during the thermal softening of the film-type adhesive for the beginning of the adhesion process. These gas volumes (inclusions) prevent an optimal adhesion of the glue in this area.